The present invention is directed to air filter configurations and, more particularly, air filters with pleats of different heights.
Air filters are well known devices in which an airstream is drawn or forced into a housing and caused to pass through a filter medium configured to remove dirt, dust and other particles entrained in the airstream. The airstream cleaned by the filter is thereafter used in devices such as internal combustion engines.
The filter element is disposed in a filter retainer or housing between an air inlet and air outlet. Generally, a seal is positioned to seal the air inlet from the air outlet so that all air passing out of the outlet has been passed through the filter element. For most automotive applications, the filter element is conventionally constructed of pleated paper with pleats facing upstream toward the airstream inlet and downstream toward the airstream outlet. These filters may be of the cylindrical, frustoconical or panel configuration. Many light duty air filters used in automotive applications to filter inlet air for internal combustion engines are configured as rectangular panels to filter the high velocity air consumed by the engines.
Heretofore, high velocity, panel-type air filters configured of pleated media filter elements have pleats of the same length. In other words, the pleat-to-pleat distance from the folds of each pleat are substantially the same for all pleats.
Where the filter paper medium is pleated with each pleat having the same length or amplitude, restriction of air flow through the filter is increased by creating turbulent air flow at the upstream side of the filter. This results in increased fuel consumption and reduced engine power.
In view of the aforementioned considerations, it is a feature of the present invention to provide a new and improved air filter which lowers restriction across the filter without reducing the filter""s capacity or efficiency to thereby provide an air filter for devices such as internal combustion engines which allows the air fed to the engines to be filtered so that the engines operate with reduced fuel consumption and increased power.
In accordance with one aspect of the invention, a configuration for an air filter element is provided wherein the air filter element is comprised of a web of filter material folded with a plurality of pleats. The air filter material has an upstream side facing toward an incoming airstream and a downstream side facing away from the incoming airstream. The web is configured of high peaks and low peaks on both the upstream side of the filter and the downstream side of the filter with the high and low peaks alternating with one another.
It is further contemplated that the filter material can be one of many types of filtering media and that the web is comprised of panels of different widths joined by folds and separated by V-shaped gaps in a series comprising wide panels, first intermediate width panels, relatively narrow width panels and second intermediate width panels, which series repeats itself in the air filter element.
A further aspect of the present invention is directed to the aforementioned structure in combination with an air intake of an internal combustion engine, whereby the aforementioned structure reduces restriction of air flow across the filter by decreasing turbulence as the airstream enters the upstream side of the filter, thereby enhancing the capacity and efficiency of the filter while providing more consistent air density on the downstream side of the filter.